To put this lens on a FX camera that will reduce the low quality image to a 5MP file is not a wise move.

Not sure I understand your logic here. If you use the lens at focal lengths where it doesn't vignette on FX, a D700 is less demanding of a lens than a DX camera of the same mp. The photo sites on a 12 mp FX sensor are larger than on a 12 mp DX sensor. So, lens resolution is not as critical.
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Robin Casady
http://www.robincasady.com/Photo/index.html